There are numerous known devices enabling a fluid to flow from a fixed pipe to a movable pipe and ensuring good fluidtightness. However, in a certain number of cases they do not give entire satisfaction.
Thus, in the case of a bottom-blast steelwork converter, which tilts about two trunnions, at least one of its two trunnions is hollow and the feed pipes for the fluids necessary for the refinement of the metal bath, for stirring it, for the dilution of the carbon monoxide, for scouring the blastpipes, or for protection of the pipes against hot wear, pass through the hollow trunnion or trunnions.
Certain of these fluids may contain powdery materials (lime, limestone flux, carbon, mineral, etc...) which are more or less abrasive.
The known rotary connectors when new operate in general in a fairly satisfactory way but in the long term they display the following disadvantages:
A. When they are worn they exhibit no precursory sign of wear and at the ultimate stage they break through suddenly, thus bringing about leakage of substantial amounts of fluids and requiring sudden stop of the metallurgical operation of refinement.
B. They include no wearing part and after wear they must be replaced entirely.
C. They are not suited to the use of powdery materials in suspension in the fluids employed.
Another disadvantage of known rotary connectors is that they have to be arranged in a straight-line pipe, which means that only one large pipe and hence only one main fluid can be admitted per hollow trunnion.